fix(rectification): keep candidate state coherent

frontend/src/components/rectification-agentic-chat.tsx

@@ -866,9 +866,10 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
   }, [initialTurns.length, onOpeningConsumed, readonly, send, shouldStartOpening]);
 
   const acceptCandidate = useCallback(async (candidateId: string) => {
-    if (!candidateResult || acceptingCandidateId || readonly) return;
+    if (!candidateResult || acceptingCandidateId || busy || readonly) return;
     setError("");
     setAcceptingCandidateId(candidateId);
+    setPending(true);
     try {
       const response = await fetch(
         `/api/rectification/cases/${encodeURIComponent(caseId)}/candidates/accept`,
@@ -916,12 +917,14 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
       onSaved?.(payload.saved_time, "accepted");
       onCompleted?.();
       await loadCaseSnapshot();
+      choiceContinuationPending.current = true;
     } catch (caught) {
       setError(caught instanceof Error ? caught.message : "暂时无法采用该候选时间");
     } finally {
       setAcceptingCandidateId(null);
+      setPending(false);
     }
-  }, [acceptingCandidateId, candidateResult, caseId, loadCaseSnapshot, onCompleted, onSaved, readonly, sessionId]);
+  }, [acceptingCandidateId, busy, candidateResult, caseId, loadCaseSnapshot, onCompleted, onSaved, readonly, sessionId, setPending]);
 
   async function copyMessage(message: RenderMessage) {
     try {